Last Updated: 05/08/2025

Diarrhoea in Dogs: A Vet Guide

Dealing with your dog's diarrhoea? Our vets explain the common causes, from simple dietary upsets to allergies or other health issues. Learn when a bland diet is enough and when a specific prescription diet is needed to soothe their stomach and aid a swift recovery.

Author: Dr Carla Paszkowski BVSc (Hons)

Reading Time: 4 minutes - short read

Most dogs will experience diarrhoea at some point in their lives, and there are many causes for this unfortunate affliction. Some dogs with a sensitive stomach may experience 'on and off' bouts of chronic mild loose stool, which may respond to a sensitive stomach diet.

But sometimes the issue is acute and can affect healthy dogs. Your dog may just have small bouts of tummy upset and quickly improve, while others can become seriously unwell. If diarrhoea continues for an ongoing period, it can lead to weight loss, dehydration, and electrolyte depletion.

When to seek immediate veterinary attention:

The loose stool has persisted for more than 2 days
The stool is watery
There is any blood or mucus in the stool
Your dog is lethargic, off their food, or vomiting
Your dog is a puppy

Main Causes of Diarrhoea in Dogs

grey puppy with blue eyes sitting on wooden floor and looking up at the camera

Dietary changes

A frequent source of diarrhoea in dogs is a sudden change in diet. Whether you've just run out of their favourite food or thought you'd try a tasty, new treat, suddenly changing a dog's diet can cause vomiting and diarrhoea. When introducing your pet to a new diet it is best to do so slowly to try and minimise any potential problems.

Read our article How to Transition to a New Pet Food for some more tips and tricks.

Eating something they shouldn't have

Dietary indiscretion, where your pooch has helped himself to something he shouldn't have, is another common cause of diarrhoea. Whether your dog has been rummaging through the garbage bin or has found a tasty morsel while out on a walk, both scenarios are likely to lead to an upset tummy. In this situation, feeding your dog a bland diet such as boiled chicken and white rice will often quickly help to resolve the diarrhoea. If however, the diarrhoea persists, your dog is vomiting frequently or seems generally unwell, it is important to seek veterinary advice and treatment.

Parasites

Another common reason for diarrhoea is parasite infection. Intestinal parasites like hookworms, whipworms, roundworms, coccidia and giardia will all cause diarrhoea. Dogs can pick up these parasites from eating contaminated meat, drinking from contaminated water, as well as coming into contact with infected animals or their faeces. Parasites are also easily transmitted from mothers to their pups, so it is especially important that puppies and pregnant or nursing females are treated for parasites regularly.

For more information about protecting your dog or puppy from worms check out our Dog Worming Guide.

Shop All Intestinal Worming for Dogs

Food sensitivities and intolerances

Much like their human owners, dogs may also have dietary sensitivities or food intolerances which can result in diarrhoea. Intolerances in dogs generally develop over time and are associated with common proteins found in many commercially prepared dog foods including beef, dairy and wheat.

If you suspect that your dog may have a food allergy or intolerance, consult your vet regarding the best course of action. They may recommend a dietary trial using a veterinary elimination diet which is specifically formulated to be hypoallergenic. If the diarrhoea resolves during the feeding trial, it may indicate a food intolerance which usually requires a special dietary formulation to be fed long term.

Some dogs can show improvements on a diet for sensitive stomachs. These diets are often formulated from highly digestible proteins, with the addition of probiotics, to support good digestion.

For more information, take a look at the Signs Your Dog May Have a Food Allergy and read more about hypoallergenic diets in our article What is the best Hypoallergenic Dog Food?

Best Diets for Supporting Food Intolerances

Shop All Digestive Support Veterinary Diets

Shop All Diets for Sensitive Stomachs

Bacterial or viral infections

Bacterial and viral infections such as parvovirus can be another serious and life-threatening cause of diarrhoea in dogs, often requiring hospitalisation for treatment and recovery. To prevent these diseases and minimise your dog's risk of diarrhoea, always ensure all vaccinations are kept up to date, and keep any unvaccinated puppies away from other dogs or areas such as parks. Puppies tend to be the most at risk of parvovirus, and suffer the worst from these types of infections.

Extra-gastrointestinal causes

There are a myriad of other of serious causes of diarrhoea in dogs that are caused by other parts of the body. These might include pancreatic issues, liver disease, tumours, or blockage of parts of the gastrointestinal tract. In any case of persistent diarrhoea ensure you contact your vet and seek emergency treatment if your dog is unwell.

Treatment of Diarrhoea in Dogs

The treatment for diarrhoea in dogs will ultimately depend on the underlying cause. However, more and more research has shown that probiotics have many health benefits for dogs, including competing with harmful germs, acting as natural antibiotics and stimulating the dog's immune system to help reduce the duration and incidence of diarrhoea.

For detailed information about the benefits of probiotics in dogs, take a read through our veterinary written article Probiotics for Dogs.

Vet Recommended Probiotics for Dogs

Shop all Probiotics for Dogs

Ultimately, the right response to your dog's diarrhoea depends entirely on the cause. A simple case of 'garbage gut' in an otherwise healthy dog may resolve quickly with a temporary bland diet and the gut-soothing support of probiotics.

However, it's critical to remember that diarrhoea can also be a red flag for more serious conditions like infections, parasites, or food allergies. Never hesitate to contact your vet if the issue is severe, contains blood, persists for more than 48 hours, or is accompanied by other warning signs like lethargy or vomiting.

History

Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.

Tue Apr 19 2022

Written by Dr Carla Paszkowski BVSc (Hons)

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About the Author

Dr Carla Paszkowski BVSc (Hons)

Veterinarian

Dr. Carla graduated from the University of Queensland in 2013 with a Bachelor of Veterinary Science and worked for a number of years in small animal clinics across South East Queensland. While Carla enjoys most facets of clinical veterinary work, she holds a special passion for feline medicine, pocket pets, and nutrition.

Diarrhoea in Dogs: A Vet Guide

When to seek immediate veterinary attention:

In this article

Main Causes of Diarrhoea in Dogs

Dietary changes

Eating something they shouldn't have

Parasites

Food sensitivities and intolerances

Best Diets for Supporting Food Intolerances

Bacterial or viral infections

Extra-gastrointestinal causes

Treatment of Diarrhoea in Dogs

Vet Recommended Probiotics for Dogs

Further Reading

History

Tue Apr 19 2022

About the Author

Dr Carla Paszkowski BVSc (Hons)

Customer Care

About Pet Circle

Caring For Your Pet

When to seek immediate veterinary attention:

In this article

Main Causes of Diarrhoea in Dogs

Dietary changes

Eating something they shouldn't have

Parasites

Food sensitivities and intolerances

Best Diets for Supporting Food Intolerances

Bacterial or viral infections

Extra-gastrointestinal causes

Treatment of Diarrhoea in Dogs

Vet Recommended Probiotics for Dogs